Two cases of bilateral occlusion of the extracranial internal carotid artery after blunt trauma to the head and neck are presented. Sixteen similar cases have been reported in the literature, and at least 150 case reports exist on unilateral blunt trauma of carotid arteries. The 25-day post-traumatic latent interval in one of our cases is the longest to date. The diagnosis of both of our cases was established by directional cw-Dopplersonography, whereas previously the only diagnostic method available in cases with negative CT scan and latent interval was angiography. In the differential diagnosis of craniocerebral or craniocervical trauma, particularly following delay between injury and onset of neurological symptoms, Dopplersonography is a necessary test additional.